COLLABORATIVE RESEARCH: Were there "too many" browser species worldwide in local faunas of the Early Miocene? Testing a global hypothesis using the Australian fossil mammal record

合作研究：世界范围内早中新世的当地动物群中是否存在“太多”食鸟物种？

• 批准号: 0958597
• 负责人: Christine Janis
• 金额: $ 11.89万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958597&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Were; there; too

COLLABORATIVE RESEARCH:Were there "too many" browser species worldwide in local faunas of the Early Miocene? Testing a global hypothesis using the Australian fossil mammal record - Christine Janis, Brown University and John Damuth, University of California, Santa BarbaraIs there evidence for a previously unrecognized worldwide change in terrestrial ecosystems approximately 12 million years ago? The PIs hypothesize that a striking pattern that they observed first in the history of the mammal faunas of North America may be one that is actually observable throughout the globe. This project will test this hypothesis by determining whether the same pattern occurred contemporaneously in the fossil record of Australia. Previous research showed that before 12-10 million years ago in North America, many ecological communities contained exceptionally high numbers of species of browsing ungulates (large leaf-eating herbivores)up to three times the numbers seen in vegetationally comparable modern-day habitats. In fact, the numbers of browser species in some places exceeded even those for modern tropical rainforests the present-day habitats with the highest biodiversity of browsers. No other members of these mammal faunas showed any elevated or unusual biodiversity, and faunas younger than 12-10 million years show only "normal" numbers of browser species (by today's standards). Why the older habitats were sometimes able to support what today would be impossibly high numbers of browsers is currently unknown. However, evidence suggests that some European and African faunas from before 12 million years ago also showed "too many" browsers, which in turn suggests a global cause. This project will answer the question of whether there were also "too many" browsers in the well-documented mammalian fossil record of Australia, and, if so, whether this phenomenon disappeared at about the same time as it did in North America. Study of museum collections from Australian localities will allow determination of the numbers of browser species at different times, based on morphology and wear of the teeth. Australia's distinct fauna and environmental history will provide a robust test of whether "too many browsers" was a global occurrence. If it wasn't, then we must look for regional or local causes; but if the global hypothesis is supported then a worldwide phenomenon becomes more likely and these results will guide and motivate the subsequent search for a global cause. The project's results will have implications not only for global environmental history and climate change, but also for any methods that attempt paleoecological interpretations for faunas older than 10 million years that use modern mammal faunas as an environmental proxy. This project will be a new international collaboration and will involve students and postdoctoral researchers.

合作研究：在中新世早期的当地动物群中，世界范围内是否有“太多”的浏览器物种？使用澳大利亚哺乳动物化石记录测试全球假设 - 布朗大学的克莉丝汀詹尼斯和圣巴巴拉加州大学的约翰达穆特有证据表明大约1200万年前陆地生态系统发生了以前未被认识的全球性变化吗？研究者们假设，他们在北美哺乳动物区系历史上首次观察到的惊人模式可能是在整个地球仪中都可以观察到的。本项目将通过确定澳大利亚的化石记录中是否同时发生了相同的模式来验证这一假设。先前的研究表明，在1200万至1000万年前的北美，许多生态群落中含有非常多的有蹄类动物（大型食叶草食动物），其数量是植被可比的现代栖息地的三倍。事实上，在某些地方，浏览器物种的数量甚至超过了现代热带雨林的数量，现代热带雨林是浏览器生物多样性最高的栖息地。这些哺乳动物群中没有其他成员表现出任何升高或不寻常的生物多样性，年龄小于1200万至1000万年的动物群只显示出“正常”数量的浏览器物种（以今天的标准）。为什么旧的栖息地有时能够支持今天不可能的大量浏览器，目前还不清楚。然而，有证据表明，1200万年前的一些欧洲和非洲动物群也显示出“太多”的浏览器，这反过来又表明了一个全球性的原因。这个项目将回答一个问题，即在澳大利亚有据可查的哺乳动物化石记录中是否也有“太多”的浏览者，如果是这样，这种现象是否与北美同时消失。对澳大利亚各地博物馆收藏品的研究将允许根据牙齿的形态和磨损来确定不同时期浏览器物种的数量。澳大利亚独特的动物群和环境历史将为“浏览者太多”是否是全球性事件提供强有力的测试。如果不是，那么我们必须寻找区域或局部原因;但如果全球假设得到支持，那么世界范围内的现象就更有可能，这些结果将指导和激励随后寻找全球原因。该项目的结果将不仅对全球环境历史和气候变化产生影响，而且对任何试图用现代哺乳动物区系作为环境代用品来解释1000万年前的动物群的古生态学方法也产生影响。该项目将是一个新的国际合作，将涉及学生和博士后研究人员。